Folded cascode operational transconductance amplifiers (OTAs) tend to have a good power supply rejection ratio at high frequencies. To illustrate, folded cascode OTAs have the ability to reject a relatively large amount of noise from a power supply. Thus, folded cascode OTAs can be used in switched capacitor circuits associated with high-frequency applications.
Switched capacitor circuits including OTAs are typically associated with two non-overlapping clock phases, a charge transfer phase and a holding phase. During the charge transfer phase, charge accumulates in an integrating capacitor of a switched capacitor circuit, while during the holding phase, charge is stored in the integrating capacitor. An OTA of a switched capacitor circuit may have a particular phase margin during the charge transfer phase and the holding phase. The phase margin of the OTA provides a measure of stability of the OTA because the phase margin indicates a tendency of the OTA toward oscillation.
In some instances, biasing currents of an OTA included in a switched capacitor circuit are reduced in order to decrease power consumption. The decreased bias currents may result in performance issues related to slew rate and settling time.